The TUI

The TUI fills the terminal's alternate screen. When a chunk streams in, bwn re-wraps only the transcript line it changes. Repaints use synchronized output, so terminals that support it draw each one as a single frame. The composer has a border and stays on screen. On launch, the composer and footer paint first, so you never see a black screen.

With --plain, or when TERM is dumb, bwn runs in line mode instead. It does not switch to the alternate screen, prints the transcript line by line, and shows no footer, spinner or popup. Its input line takes Esc, Ctrl+C, Ctrl+D, Shift+Tab, and ↑/↓ for history. The rest of this page describes the full-screen TUI.

Diffs

bwn draws every edit with a gutter of old and new line numbers, added rows in green and removed rows in red, and the changed span highlighted within each line. The dark and light themes also tint the background of added and removed rows. The ansi theme keeps the terminal's own background there. Each diff appears once. When bwn applies a change, it prints an edit header with the path and the added and removed counts. When bwn asks before a change, the diff appears above the approval question, and bwn prints nothing under the edit header. Otherwise the diff appears under it. A diff shows up to 40 lines, and a new file shows its first 20. File paths in edit headers are OSC 8 links, so clicking one opens the file in your default app.

The theme setting picks dark, light or ansi. Its default, auto, picks light on a light terminal background and dark otherwise. /theme switches the theme and saves your choice.

Autocomplete

Typing / opens a popup that lists every command with a description and narrows the list with each keystroke. @ completes file paths, and @kb: and @symbol: query the project knowledge base.

Inline images

Paste a screenshot with Ctrl+V or drop a file onto the terminal, and bwn draws the image in the transcript before you send it. When you type a path such as @shot.png, bwn draws the image when it attaches the file to the prompt you send. On kitty and Ghostty, the image appears with its real pixels. bwn uploads it once as a PNG through the kitty graphics protocol, and the transcript rows hold placeholder cells. The image therefore scrolls, wraps and repaints the same way text does. This tier reads PNG files directly and needs ffmpeg only for other formats. Inside tmux, this works when your tmux config has set -g allow-passthrough on. bwn deletes the uploaded image from the terminal when you exit. When bwn starts, it asks the terminal whether it supports Sixel. Terminals that do, such as Windows Terminal 1.22 or later, WezTerm, foot and mlterm, also get real pixels. bwn decodes the image with ffmpeg and draws it over Sixel. On every other truecolor terminal, bwn decodes the image with ffmpeg and draws it as half-block art. In every tier the image takes at most half the window's width, up to 80 columns, and a third of the rows above the composer, up to 16 rows. In the kitty and Sixel tiers, bwn never draws the image larger than its native size. To override the detection, set the images settings key to auto, kitty, sixel, blocks or off, or set BWN_IMAGES.

Code and tables

A zero-dependency lexer highlights fenced code blocks in Rust, C/C++, JavaScript/TypeScript, Python, Go, Java/Kotlin/Swift, shell, Ruby/PHP/Lua, SQL, JSON, YAML, TOML, CSS, HTML and diffs. It runs once, when the closing fence arrives, and never per streamed token. bwn collects pipe tables as they stream in and draws each one as a single aligned block. The block has a bold header and a ─┼─ rule. Columns follow the :--, :-: and --: alignment markers and shrink with … instead of wrapping. --- rules, #### headings, - [ ] task lists and ~~strikethrough~~ render too.

Footer and notifications

The footer always names the model. When the agent is idle, the footer also names the permission mode. While the agent works, the footer replaces the permission mode with a spinner, the elapsed time, an estimate of streamed tokens per second, and a hint that Esc interrupts. Windows Terminal, Ghostty and ConEmu also show a progress state on the taskbar. While the window is unfocused, bwn sends a desktop notification when a turn of eight seconds or more ends, and when it waits for you at an approval or a question. bwn sends each one over OSC 99 and OSC 777, adds OSC 9 on iTerm2, WezTerm and Windows Terminal, and rings the bell. Set "notify": "always" or "off" to change that. If you scroll back to read earlier output, the view does not move when new output streams in.

Multimodal

Ctrl+V pastes a clipboard screenshot and draws it inline as you paste. When you send the prompt, bwn attaches the picture to it. If the model takes no images or the picture is over 5 MB, bwn prints a warning and sends the prompt without the picture. @clip.mp4 attaches a video as frames that ffmpeg samples. Paths to generated .docx files open in your default app, such as Word, when you click them. See Multimodal input for details.

Keys

/vim turns vim-style modal editing on or off. The cursor shape shows whether you are in NORMAL, INSERT or VISUAL mode.